Direct α-iodination of some carboxylic acids, namely, acetic acid, propionic acid, butyric acid, and valeric acid, using iodine-copper salt, gave the corresponding α-iodo carboxylic acid in high yield. This new synthetic method afforded several advantage over classical α-iodo carboxylic acid procedures.
[Kirk, Benjamin B.; Trevitt, Adam J.; Poad, Berwyck L.J.; Blanksby, Stephen J. International Journal of Mass Spectrometry, 2013 , vol. 351, p. 81 - 94]